Electric switch.



r. KRAIA (i. HONOLD.

ELECTRC SWITCH.

APPLICATION FILED MAR.9,1915. D m uA mtentad May lo, 19315.

s sHEETssHsaT 1.

E & G,HONOLD.

ELECTRIC SWITCH.

KRAT

APPLICATION FILED MAR` 9, 1915:

Patented May16, 1916.

3 SHEETS--SHEET 2.

lIl xMTMESSES F. KRATZ & G. HONOLD.

ELECTRIC SWITCH.

APPLICATION FILED MAILQ, I9I5.

LESS/997% Patented May I6, 1916.

3 SHEETS-SHEET 3.

I L u v FRANZ KRATZ AND GOTTLOB HON OLD.

FIRM OF ROBERT BOSCH, GF STUTTGART, GERMNY.

ELECTRIC SWITCH Application filed March 9, 1915.

To aZZ whom t may conce/m i Be it known that we, F RANz KRATz'ga subject of the Emperor of Germany, residing at and whose post-otlice address is Schloss- .strasse 59:L Stuttgart, Germany, and Go'rTLoB HoNoLD, a. subject of the Emperor 'of Germany, residing dress is Militarstrasse et, i Stuttgart, Germany, haveinvented certain new and useful Improvements in Electric Switches; and we do hereby declare the following to be afnll, clear, and exact'description of the invention, such as will enable others skilled in the art? to which it appertains to make and use the same.

The electric switch of the present invention embodies improvements especially -applicable ternal combustion engines on automobiles, motor boats, and other moving vehicles.

The features of novelty will be Vparticulai-ly pointed out in the following description, and the appended claims, taken in con-` nection with the accompanying drawings in which- Figure l is a sectional elevation through the switch in the depressed position; Fig. 2 is a section on line 2-2 of Fig. 1;* Figs'. 3 and 4: are sections corresponding to Figs. 1 and 2,with the switch locked in its inoperative position; Fig. 5 isa view of the removable key; Fig. 6 is a section on line 6`5 of Fig. l, drawn on an enlarged scale, Fig. 7 is an enlarged horizontal section through a switch bridge;4 Fig. 8 is a section on line 8`8 of Fig. '1; and Fig. 9 is a section on line 9 9 of Fig. 7. F l0 is a side elevation of the switch partly in section. Fig. 1l is a front view showing an inserted resistance. Fig. 12 is a rear View. Fig. 13 is a horizontal section in the line l3-13 of Fig. 12.

The hollow switch shaft Z) is longitudinally movable in: the bearing a of the switch housing a, and it carries a head member c having a hinged cap cl.. The'lock bar c is tted in the interior of the switch shaft and is provided at the upper end with the key hole 'f and at the other end with the projecting tongues g adapted to slide in the slots it .of the upstanding stationary guide These slots terminate in horizontal loclnng slots Z1. into which the tongues g may be turned to lock the switch shaft against depression from its raised position,

" Specication of Letters Patent.

at and Whose post-office adi Ascrewed on the end Patented May 16, 1916. serial No. 13,200. i'

the lock` bar e being longitudinally movable with the switch shaft-and rotatable therein. A removable key g fits in the key hole f and is adapted to? turn the lock bar e when tongues g are in registry with the locking slots if to thereby lock the switch in inoperative position against unauthorized use, and to vunlock the switch shaft for movement to its operative position,YY vided for the purpose of preventing the entrance of foreign matter into the switch housing at other times. The coil compression spring Zr: post z', and the under side of the head `member c, thus tending to in its raised position, shown in Figs. 3 and 4.

The switch shaft ZJ carries the conducting switch bridge Z and 'also an arm Z', which with the conducting switch bridge Z2 slidably mounted on the upstanding guide post z". The metal contact studs m are mounted on'the insulating material lw and are electrically connected to the binding the'cap Z being prol.

presses against the head of the hold the switch shaft posts-'m'. The studs may be segmental and i on the post i. arelalike, andeach is composed of bent lamistantially that part the switch Y shaft b. insulation ZJ insulates the switch shaft Z2 and the posts c', i', from the switch bridges Z and Z2. rhe nut o, ot' the switch'Sft forces the switch bridge against; the member 0,

t will be observed that the contact surfaces of the studs m lie in parallel planes, which, together with the arrangement of the laminations Z, Z2, .and the fastening means therefor, bringsabout an equalization of the pressure on the studs such that neither the a set posii switch shaft I)l nor the sleeve Z3 is forced to a vertically inclined position. In this way binding action is prevented.

A resistance made up of one or more strips r of nickelin, or other suitable metal, is laid around the sides and bottom of the switch housing a. The resistance metal is insulatedon both surfaces by strip mica s, and the outside is covered by a metal sheet u fastenedto the switch housing a. by rivets extending between the strips. The two ends of strip r are electrically connected to binding posts c which may be connected to the binding posts m or to the circuit, according to any desired arrangements.

Having thus described ouil invention, what we claim is:

1. ln an electric switchfth combination with contact studs, a conducting switch bridge slidable along said contaet'studs, and a longitudinally movable switch shaft fastened to the switch bridge and constructed and arranged to move the switch bridge from an inoperative to an operative'position in engagement with the contact studs, of locking mechanism preventing thc movement of the switch bridge to its operative position and comprising a locking bar carried by the 'switch shaft so as to turn relatively thereto, and a catch cooperative with the locking bar when the locking bar is turned relatively to the switchshaft.

2. In an electric switch,the combination with switch studs, a conducting switch bridge slidable along said 'contact studs, an upstandin g post having a longitudinal guiding slot terminating in a horizontal locking slet, and a longitudinally movable switch shaft constructed and arranged to move the switch bridge longitudinally, of a locking bar carried by the switch shaft and having a tongue slidable in the 0aiding slot and rotatable in the locking s ot, and a removable i key for turning the tongue into the locking slet te thereby lock the switch shaft against longitudinal movement when the switch bridge is disengaged from contact studs.

3. In an electric switch, the combination with contact studs, a conducting switch bridge slidablealong said contact studs, and a longitudinally movable switch sha ft having a hinged cover on which the operating pressure is applied and heilig constructed and arranged to move the switch bridge from an operative position in engagement with the contact studs, of key locking meehanism embodying a removable key insertihle in operative position when its cover is raised to lock the switch bridge against movement to its operative position.

4. In an electric switch, contact studs having contact surfaces lying in parallel planes, a conducting switch bridge of resilient material engaging the studs, a switch shaft fastened tp the switch bridge and hav ing a smooth interior and a post on which the switch shaft is freely slidable and also freely rotatable to permit turning movement thereof for equalizing unbalanced.'pressure between the switch bridge and the studs.

5. In an electric switch, contact studs having contact surfaces lying in parallel planes, a conducting switch bridge of bent lai'ninations having edge on contact with the studs, apertured clamping plates having flanges embracing the laminations at the bent portion to prevent spreading thereof, a switch shaft passing through the clamping plates and fastened thereto, and a bearing rotatably mounting the switch shaft to permit turning movement thereof for equalizing unbalanced4 pressure between the switch bridge and the studs.

In testimony whereofwe affix our signatures, in presence of two witnesses.

FRANZ KR-AIZ. GOTTLOl lIONOLl). Witnesses:

PAUL WoLrAs'r, Anom Linn-mas. 

